Without a doubt. I have had insightful, but critical comments with a dozen karma suddenly downvoted into oblivion. Really lowered my expextations of having meaningful dialouge on HN.
I have experienced that frequently. And I think it is easily explained by normal human behaviors.
People see comments that they don't like -> They send the link to their group of friends -> Their friends who share the same sentiment downvotes you in quick successions.
